Fatigue is a disease that generally involves feelings of weariness (tiredness) and malaise (lassitude) as main symptoms but which is also accompanied by varied other symptoms including sleep disorder and lowered motivation. Feelings of weariness (tiredness) and malaise (lassitude) are one of the important alarm signals for a certain abnormality in the body and even healthy persons may perceive fatigue if they take heavy exercise, work for a prolonged period, or when they are given extreme stress. Such physiological fatigue is usually restored to the initial normal state by rest and will not last for long. According to “A Survey on Public Perception of Health” conducted by the Prime Minister's Office in 1985, about 60% plus of the people surveyed complained of fatigue but 70% of those who complained of fatigue said that “their fatigue was restored by a night's sleep.” However, modern people are in many cases forced to work for a prolonged period of time or given extreme stress and yet hey have difficulty taking enough rest, so they frequency find it difficult to recover from feelings of weariness (tiredness) or malaise (lassitude). According to the epidemiological research conducted by the fatigue survey study group of the Health and Welfare Ministry in 1999, the proportion of the people who perceived fatigue remained unchanged and accounted for about 60% but then as much as 60% of those people were reported to have felt tired for more than six months. Thus, in the past 14 years, more people have become afflicted with chronic fatigue, indicating a change in the nature of fatigue (Non-Patent Document 1).
A very recent topic related to fatigue is chronic fatigue syndrome (CFS) which is considered to be one of intractable disorders. In Europe and the U.S., the first onset of this disorder was reported almost 20 years ago but here in Japan it was not until about 1991 that a fact-finding survey was launched by a dedicated study group of the Health and Welfare Ministry. General symptoms of chronic fatigue syndrome include systemic feelings of weariness (tiredness) and malaise (lassitude), slight fever, lymph node dilation, muscle pain, joint pain, and psychoneurotic symptoms, all being so prolonged as to potentially interfere with the daily life of the affected individual. Another topic of the day is “death by overwork” which presents itself as a big social problem. Death by overwork is defined as a sudden death due to prolonged overloaded work. The problem of death by overwork is recognized to be of extreme importance from medical, economic and social viewpoints.
Under these circumstances, so-called “anti-fatigue substances” have been proposed, such as those which are capable of relieving the fatigue that is experienced after taking heavy exercise, working for a prolonged time, or being given excessive stress, and those which are capable of recovery from fatigue to the normal state. For example, certain kinds of amino acid compositions (Patent Document 1), L-carnitine and histidine-related dipeptides (Patent Document 2), hawthorn extracts (Patent Document 3) and the like have been reported to have a body strength increasing action. In addition, nutrition support compositions containing ascorbic acid have been shown to be useful for the purpose of furnishing nutrition when one has lost their bodily strength due, for example, to exercise or at such times that one is tired (Patent Document 4).
The above-mentioned ascorbic acid is also known to be effective in symptomatic therapy for treating chronic fatigue syndrome (Non-Patent Document 2), and it has also been suggested that acetyl-L-carnitine is effective in the treatment of chronic fatigue syndrome (Patent Document 5).
As regards sesamin and/or episesamin, the Assignee of the subject application has shown that they have an autonomic nerve regulating action (Patent Document 6). They are also shown to have an action for alleviating the symptoms of withdrawal from alcohol or tobacco intoxication (Patent Document 7). However, none of these documents suggest or disclose the anti-fatigue action.    [Patent Document 1] Official Gazette of JP 9-124473 A    [Patent Document 2] Official Gazette of JP 2001-046021 A    [Patent Document 3] Official Gazette of JP 8-47381 A    [Patent Document 4] Official Gazette of JP 6-327435 A    [Patent Document 5] Official Gazette of JP 8-26987 A    [Patent Document 6] International Publication WO 2004-105749    [Patent Document 7] Official Gazette of U.S. Pat. No. 4,427,694    [Non-Patent Document 1] M. Inoue et al. “Hirou no Kagaku (Science on Fatigue)” published by Kodansha on May 20, 2001, p. 222-228    [Non-Patent Document 2] In Vivo (1996) November-December; 10(6):585-96